The present invention relates to a short-circuit member that short-circuits predetermined segments to each other so that they have the same potential, a commutator having the short-circuit member, an armature having the commutator, and a method for manufacturing the short-circuit member.
In a motor such as a direct-current motor having a commutator and feeding brushes sliding against the commutator, a current is supplied to armature coils of an armature through the feeding brushes and the commutator. The commutator has a number of segments, and predetermined ones of the segments are short-circuited by a short-circuit member. By short-circuiting the predetermined segments, a current is supplied to segments that are not contacting the feeding brushes. The number of feeding brushes can be reduced.
For example, Japanese Laid-Open Patent Publication No. 2005-137193 discloses a short-circuit member that is formed by stacking a first conductor member group and a second conductor member group. Each of the first and second conductor member group includes conductor members the number of which is equal to the number of the segments of the commutator. The conductor members in each conductor member group are arranged to form a circle. Each conductor member has an outer terminal located at an outer portion with respect to the radial direction of the corresponding conductor member group, an inner terminal located at an inner portion with respect to the radial direction of the corresponding conductor member group, and a coupling portion coupling the outer terminal and the inner terminal to each other. A hook portion extending radially outward of the corresponding conductor member group is formed in the outer terminal of each conductor member. The first conductor member group and the second conductor member group are stacked on each other such that the outer terminals of the first conductor member group and the outer terminals of the second conductor member group are aligned and the inner terminals of the first conductor member group and the inner terminals of the second conductor member group are aligned. The aligned outer terminals are joined, and the aligned inner terminals are joined, so that the first and second conductor member groups are integrated. The hook portions of the outer terminals of the integrated first and second conductor member groups are connected to the corresponding segments. Some of the hock portions are engaged with end portions of the corresponding armature coils.
In the short-circuit member of the above described publication, each outer terminal of the first conductor member group is joined with the corresponding one of the outer terminals of the second conductor member group, and each inner terminal of the first conductor ember group is joined with the corresponding one of the inner terminals of the second conductor member group. In other words, joining is required at a number of positions. This complicates the operation for integrating the first conductor member group and the second conductor member group.